Assertion : Darwin's finches show a variety of beaks suited for eating large seeds, flying insects and cactus seeds.

Reason : Ancestral seed-eating stock of Darwin's finches radiated out from South American mainland to different geographical areas of the Galápagos Islands, where they found competitor-free new habitats.

Assertion : Atavism is the reappearance of disappeared ancestral characters.

Reason : Third molars and hair on body are examples of atavism.

Assertion : Petrified fossils contain hard parts of organisms.

Reason : Moulds and casts lack the remains of organisms.

When two related populations occupy geographically or spatially separate areas, they are called
Or

The organisms separated by geographical barriers are termed